SANTA FE, N.M., March 20 -- As men and women add extra fat over the years, a silent killer -- high blood pressure -- is creeping up along with the numbers on the weight scales, researchers reported today at the American Heart Association's epidemiology and prevention conference.
The study's author, Roger M. Siervogel, Ph.D., says, "Previous studies have found that high blood pressure can be lowered by weight loss, but this study is the longest running one to look at the long-term changes in body fat and blood pressure in men and women and to put a number on the impact of changes in body fat on blood pressure." Siervogel is professor and director of the division of human biology, department of community health at Wright State University School of Medicine, Dayton, Ohio.
On average, six to 12 percent of the variation in the rate of change in the blood pressure among participants was explained by changes in extra body fat, he says. In women, 10 to 15 percent of the change in blood pressure was accounted for by changes in increased body fat. In men, it produced six to eight percent of the variation.
Particularly in women, long-term increases in body fat are associated with increases in blood pressure, the researchers report.
The Dayton researchers measured body fat in 227 men and 254 women, all participants in the Fels Longitudinal Study, which began in 1929. The healthy participants, 18 to 71 years old, were followed for an average of 13 years with multiple examinations studying changes in body fat and blood pressure.
Measurements and blood pressure were taken an average of four times. On average, each participant gained several pounds of fat a year, Siervogel says. "We found that there was a relationship between fat and blood pressure. People getting fatter at a higher rate also were the ones who tended to have their blood pressure increasing at a higher rate," he says. "Those with lower levels of changes in body fat tended to have smaller increases, and in some cases, decreases in blood pressure."
Measurements included total body fat, fat-free mass, and percent of body fat, all determined by hydrostatic weighing in which the participants were weighed in the water. The body mass index, based on weight and height, also was determined. Blood pressures were taken at the same examination.
While these findings explain part of the rise in blood pressure, Siervogel warned that other factors such as behavior, diet and alcohol intake also are involved.
Individuals who want to keep their blood pressure in check should not gain weight, he says. "If your blood pressure is already high, then losing weight potentially will have a positive effect," he says.
The study was presented at the American Heart Association's 38th Annual Conference on Cardiovascular Disease Epidemiology and Prevention.
Other researchers involved in the study are Wayne Wisemandle, Fels study project coordinator; Bradford Towne, Ph.D.; Michele Maynard; Shumei S. Guo, Ph.D.; William Cameron Chumlea, Ph.D., of Wayne State University School of Medicine, Yellow Springs, Ohio.
Media advisory: Dr. Siervogel can be reached at (937) 767-6915. (Please do not publish telephone number.)
NR 98-4867(Epi98/Siervo)